Following yesterday's teleconference I would like to continue
discussion on this support for arbitrary datatypes in a query.
I suggested that if the support is really for any arbitrary
datatype, for a DAWG recommendation compatible RDF query
processor we need to lay a set of minimal datatypes it needs
to support. This would enable us to lay a minimal set of
operators that operate on these datatypes.
I suggest the minimal set of datatypes would be a
subset of all XML Schema datatypes. I leave it up to
further discussion to see which ones are truly necessary.
Janne
> A client wishes to discover all resources which are of rdf:type
> ex:Person, and have an ex:ageInYears which is between "16"^^ex:count
> and "18"^^ex:count, inclusive.
>
> The client is aware of a knowledge source from which such
> resources might be discovered.
>
> Following the DAWG recommendation, the client formulates a query
> which expresses the desired characteristics to match and submits
> the query to the knowledge source.
>
> The knowledge source returns zero or more resource descriptions
> describing the matched resources.
>
> --
>
> I deliberately used unknown datatypes in this example to illustrate
> the need to be able to allow arbitrary datatypes in input queries,
> regardless of what datatypes a particular query resolution engine
> may be able to handle.
>
> Note that if the client is able to include auxiliary knowledge
> which may be relevant to resolution of the query along with
> the query itself (e.g. in a single input RDF graph) this would allow
> the client to provide information about the terminology used
> in the query, such as about the nature of particular datatypes,
> their relationship to other datatypes, and even references to
> formal definitions of the datatypes which could be used by the
> knowledge source to evaluate typed literals and perform comparisons.
> E.g. the auxiliary knowledge could indicate an XML Schema which
> defines the datatype in question, and if the knowledge source is
> able to understand XML Schemas, could load and utilize to deal
> with values of that datatype.
>
> --
>
> Patrick Stickler
> Nokia, Finland
> patrick.stickler@nokia.com
>
>
>
--
Janne Saarela <janne.saarela at profium.com>
Profium, Lars Sonckin kaari 12, 02600 Espoo, Finland